Phosphorescent heteroleptic phenylbenzimidazole dopants

ABSTRACT

Novel phosphorescent heteroleptic iridium complexes with benzimidazole and phenylpyridine ligands are provided. These iridium complexes can improve OLED properties, and are useful in white light applications.

The claimed invention was made by, on behalf of, and/or in connectionwith one or more of the following parties to a joint universitycorporation research agreement: Regents of the University of Michigan,Princeton University, The University of Southern California, and theUniversal Display Corporation. The agreement was in effect on and beforethe date the claimed invention was made, and the claimed invention wasmade as a result of activities undertaken within the scope of theagreement.

FIELD OF THE INVENTION

The present invention relates to compounds suitable for incorporationinto OLED devices, specifically the compounds comprise heterolepticiridium complexes.

BACKGROUND

Opto-electronic devices that make use of organic materials are becomingincreasingly desirable for a number of reasons. Many of the materialsused to make such devices are relatively inexpensive, so organicopto-electronic devices have the potential for cost advantages overinorganic devices. In addition, the inherent properties of organicmaterials, such as their flexibility, may make them well suited forparticular applications such as fabrication on a flexible substrate.Examples of organic opto-electronic devices include organic lightemitting devices (OLEDs), organic phototransistors, organic photovoltaiccells, and organic photodetectors. For OLEDs, the organic materials mayhave performance advantages over conventional materials. For example,the wavelength at which an organic emissive layer emits light maygenerally be readily tuned with appropriate dopants.

OLEDs make use of thin organic films that emit light when voltage isapplied across the device. OLEDs are becoming an increasinglyinteresting technology for use in applications such as flat paneldisplays, illumination, and backlighting. Several OLED materials andconfigurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and5,707,745, which are incorporated herein by reference in their entirety.

One application for phosphorescent emissive molecules is a full colordisplay. Industry standards for such a display call for pixels adaptedto emit particular colors, referred to as “saturated” colors. Inparticular, these standards call for saturated red, green, and bluepixels. Color may be measured using CIE coordinates, which are wellknown to the art.

One example of a green emissive molecule is tris(2-phenylpyridine)iridium, denoted Ir(ppy)₃, which has the following structure:

In this, and later figures herein, we depict the dative bond fromnitrogen to metal (here, Ir) as a straight line.

As used herein, the term “organic” includes polymeric materials as wellas small molecule organic materials that may be used to fabricateorganic opto-electronic devices. “Small molecule” refers to any organicmaterial that is not a polymer, and “small molecules” may actually bequite large. Small molecules may include repeat units in somecircumstances. For example, using a long chain alkyl group as asubstituent does not remove a molecule from the “small molecule” class.Small molecules may also be incorporated into polymers, for example as apendent group on a polymer backbone or as a part of the backbone. Smallmolecules may also serve as the core moiety of a dendrimer, whichconsists of a series of chemical shells built on the core moiety. Thecore moiety of a dendrimer may be a fluorescent or phosphorescent smallmolecule emitter. A dendrimer may be a “small molecule,” and it isbelieved that all dendrimers currently used in the field of OLEDs aresmall molecules.

As used herein, “top” means furthest away from the substrate, while“bottom” means closest to the substrate. Where a first layer isdescribed as “disposed over” a second layer, the first layer is disposedfurther away from substrate. There may be other layers between the firstand second layer, unless it is specified that the first layer is “incontact with” the second layer. For example, a cathode may be describedas “disposed over” an anode, even though there are various organiclayers in between.

As used herein, “solution processible” means capable of being dissolved,dispersed, or transported in and/or deposited from a liquid medium,either in solution or suspension form.

A ligand may be referred to as “photoactive” when it is believed thatthe ligand directly contributes to the photoactive properties of anemissive material. A ligand may be referred to as “ancillary” when it isbelieved that the ligand does not contribute to the photoactiveproperties of an emissive material, although an ancillary ligand mayalter the properties of a photoactive ligand.

As used herein, and as would be generally understood by one skilled inthe art, a first “Highest Occupied Molecular Orbital” (HOMO) or “LowestUnoccupied Molecular Orbital” (LUMO) energy level is “greater than” or“higher than” a second HOMO or LUMO energy level if the first energylevel is closer to the vacuum energy level. Since ionization potentials(IP) are measured as a negative energy relative to a vacuum level, ahigher HOMO energy level corresponds to an IP having a smaller absolutevalue (an IP that is less negative). Similarly, a higher LUMO energylevel corresponds to an electron affinity (EA) having a smaller absolutevalue (an EA that is less negative). On a conventional energy leveldiagram, with the vacuum level at the top, the LUMO energy level of amaterial is higher than the HOMO energy level of the same material. A“higher” HOMO or LUMO energy level appears closer to the top of such adiagram than a “lower” HOMO or LUMO energy level.

As used herein, and as would be generally understood by one skilled inthe art, a first work function is “greater than” or “higher than” asecond work function if the first work function has a higher absolutevalue. Because work functions are generally measured as negative numbersrelative to vacuum level, this means that a “higher” work function ismore negative. On a conventional energy level diagram, with the vacuumlevel at the top, a “higher” work function is illustrated as furtheraway from the vacuum level in the downward direction. Thus, thedefinitions of HOMO and LUMO energy levels follow a different conventionthan work functions.

More details on OLEDs, and the definitions described above, can be foundin U.S. Pat. No. 7,279,704, which is incorporated herein by reference inits entirety.

SUMMARY OF THE INVENTION

A compound comprising a heteroleptic iridium complex having the formula:

Formula I, is provided. R₁, R₃, R₄, R₅ and R₆ represent mono-, di-, tri-or tetra-substitution. R₁, R₂, R₃, R₄, R₅ and R₆ are each independentlyselected from the group consisting of hydrogen, deuterium, halide,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof. Additionally,R₁, R₃, R₄, R₅ and R₆ are optionally fused and may be furthersubstituted, and n is 1 or 2.

In one aspect, n is 2. In another aspect, n is 1.

In one aspect, R₂ is aryl or substituted aryl. In another aspect, R₂ isa 2,6-disubstituted aryl. In one aspect, R₂ is alkyl. In another aspect,R₂ is

In one aspect, R₃, R₄, R₅ and R₆ are each independently selected fromthe group consisting of hydrogen and alkyl, and wherein at least one ofR₃, R₄, R₅ and R₆ is alkyl. In one aspect, R₅ is aryl. In anotheraspect, R₆ is aryl.

In one aspect, R₁, R₃, and R₅ are hydrogen.

Specific non-limiting examples of a compound of Formula I are provided.In one aspect, the compound is selected from the group consisting ofCompound 1-Compound 100.

A first device is also provided. The first device comprises a firstorganic light emitting device, further comprising an anode, a cathode,and an organic layer, disposed between the anode and the cathode,comprising a compound having the formula:

R₁, R₃, R₄, R₅ and R₆ represent mono-, di-, tri- or tetra-substitution.R₁, R₂, R₃, R₄, R₅ and R₆ are each independently selected from the groupconsisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof. Additionally, R₁, R₃, R₄,R₅ and R₆ are optionally fused and may be further substituted, and n is1 or 2.

In one aspect, the organic layer is an emissive layer and the compoundis an emissive dopant. In one aspect, the organic layer is an emissivelayer and the compound is a non-emissive dopant. In another aspect, theorganic layer further comprises a host.

In one aspect, the host comprises a triphenylene containing benzo-fusedthiophene or benzo-fused furan, wherein any substituent in the compoundis an unfused substituent independently selected from the groupconsisting of C_(n)H_(2n+1), OC_(n)H_(2n+1), OAr₁, N(C_(n)H_(2n+1))₂,N(Ar₁)(Ar₂), CH═CH—C_(n)H_(2n+1), C≡CHC_(n)H_(2n+1), Ar₁, Ar₁—Ar₂,C_(n)H_(2n)—Ar₁, or no substitution. Ar₁ and Ar₂ are independentlyselected from the group consisting of benzene, biphenyl, naphthalene,triphenylene, carbazole, and heteroaromatic analogs thereof, and n isfrom 1 to 10.

In one embodiment, the host has the formula:

In one aspect, the host is a metal complex.

In one aspect, the first device is a consumer product. In anotheraspect, the first device is an organic light-emitting device. In oneaspect, the first device further comprises a second emissive dopanthaving a peak wavelength of between 400 to 500 nanometers. In oneaspect, the second emissive dopant is a fluorescent emitter. In anotheraspect, the second emissive dopant is a phosphorescent emitter.

In one aspect, the first device comprises a lighting panel. In oneaspect, the first device further comprises a first organiclight-emitting device comprising a compound of Formula I and a secondlight-emitting device separate from the first organic light-emittingdevice comprising an emissive dopant having a peak wavelength of between400 to 500 nanometers. In another embodiment, the first device comprisesan organic light-emitting device having a first emissive layercomprising a compound of Formula I and a second emissive layercomprising an emissive dopant having a peak wavelength of between 400 to500 nanometers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an organic light emitting device.

FIG. 2 shows an inverted organic light emitting device that does nothave a separate electron transport layer.

FIG. 3 shows a compound of Formula I.

DETAILED DESCRIPTION

Generally, an OLED comprises at least one organic layer disposed betweenand electrically connected to an anode and a cathode. When a current isapplied, the anode injects holes and the cathode injects electrons intothe organic layer(s). The injected holes and electrons each migratetoward the oppositely charged electrode. When an electron and holelocalize on the same molecule, an “exciton,” which is a localizedelectron-hole pair having an excited energy state, is formed. Light isemitted when the exciton relaxes via a photoemissive mechanism. In somecases, the exciton may be localized on an excimer or an exciplex.Non-radiative mechanisms, such as thermal relaxation, may also occur,but are generally considered undesirable.

The initial OLEDs used emissive molecules that emitted light from theirsinglet states (“fluorescence”) as disclosed, for example, in U.S. Pat.No. 4,769,292, which is incorporated by reference in its entirety.Fluorescent emission generally occurs in a time frame of less than 10nanoseconds.

More recently, OLEDs having emissive materials that emit light fromtriplet states (“phosphorescence”) have been demonstrated. Baldo et al.,“Highly Efficient Phosphorescent Emission from OrganicElectroluminescent Devices,” Nature, vol. 395, 151-154, 1998;(“Baldo-I”) and Baldo et al., “Very high-efficiency green organiclight-emitting devices based on electrophosphorescence,” Appl. Phys.Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), which are incorporatedby reference in their entireties. Phosphorescence is described in moredetail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporatedby reference.

FIG. 1 shows an organic light emitting device 100. The figures are notnecessarily drawn to scale. Device 100 may include a substrate 110, ananode 115, a hole injection layer 120, a hole transport layer 125, anelectron blocking layer 130, an emissive layer 135, a hole blockinglayer 140, an electron transport layer 145, an electron injection layer150, a protective layer 155, and a cathode 160. Cathode 160 is acompound cathode having a first conductive layer 162 and a secondconductive layer 164. Device 100 may be fabricated by depositing thelayers described, in order. The properties and functions of thesevarious layers, as well as example materials, are described in moredetail in U.S. Pat. No. 7,279,704 at cols. 6-10, which are incorporatedby reference.

More examples for each of these layers are available. For example, aflexible and transparent substrate-anode combination is disclosed inU.S. Pat. No. 5,844,363, which is incorporated by reference in itsentirety. An example of a p-doped hole transport layer is m-MTDATA dopedwith F₄-TCNQ at a molar ratio of 50:1, as disclosed in U.S. PatentApplication Publication No. 2003/0230980, which is incorporated byreference in its entirety. Examples of emissive and host materials aredisclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which isincorporated by reference in its entirety. An example of an n-dopedelectron transport layer is BPhen doped with Li at a molar ratio of 1:1,as disclosed in U.S. Patent Application Publication No. 2003/0230980,which is incorporated by reference in its entirety. U.S. Pat. Nos.5,703,436 and 5,707,745, which are incorporated by reference in theirentireties, disclose examples of cathodes including compound cathodeshaving a thin layer of metal such as Mg:Ag with an overlyingtransparent, electrically-conductive, sputter-deposited ITO layer. Thetheory and use of blocking layers is described in more detail in U.S.Pat. No. 6,097,147 and U.S. Patent Application Publication No.2003/0230980, which are incorporated by reference in their entireties.Examples of injection layers are provided in U.S. Patent ApplicationPublication No. 2004/0174116, which is incorporated by reference in itsentirety. A description of protective layers may be found in U.S. PatentApplication Publication No. 2004/0174116, which is incorporated byreference in its entirety.

FIG. 2 shows an inverted OLED 200. The device includes a substrate 210,a cathode 215, an emissive layer 220, a hole transport layer 225, and ananode 230. Device 200 may be fabricated by depositing the layersdescribed, in order. Because the most common OLED configuration has acathode disposed over the anode, and device 200 has cathode 215 disposedunder anode 230, device 200 may be referred to as an “inverted” OLED.Materials similar to those described with respect to device 100 may beused in the corresponding layers of device 200. FIG. 2 provides oneexample of how some layers may be omitted from the structure of device100.

The simple layered structure illustrated in FIGS. 1 and 2 is provided byway of non-limiting example, and it is understood that embodiments ofthe invention may be used in connection with a wide variety of otherstructures. The specific materials and structures described areexemplary in nature, and other materials and structures may be used.Functional OLEDs may be achieved by combining the various layersdescribed in different ways, or layers may be omitted entirely, based ondesign, performance, and cost factors. Other layers not specificallydescribed may also be included. Materials other than those specificallydescribed may be used. Although many of the examples provided hereindescribe various layers as comprising a single material, it isunderstood that combinations of materials, such as a mixture of host anddopant, or more generally a mixture, may be used. Also, the layers mayhave various sublayers. The names given to the various layers herein arenot intended to be strictly limiting. For example, in device 200, holetransport layer 225 transports holes and injects holes into emissivelayer 220, and may be described as a hole transport layer or a holeinjection layer. In one embodiment, an OLED may be described as havingan “organic layer” disposed between a cathode and an anode. This organiclayer may comprise a single layer, or may further comprise multiplelayers of different organic materials as described, for example, withrespect to FIGS. 1 and 2.

Structures and materials not specifically described may also be used,such as OLEDs comprised of polymeric materials (PLEDs) such as disclosedin U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated byreference in its entirety. By way of further example, OLEDs having asingle organic layer may be used. OLEDs may be stacked, for example asdescribed in U.S. Pat. No. 5,707,745 to Forrest et al, which isincorporated by reference in its entirety. The OLED structure maydeviate from the simple layered structure illustrated in FIGS. 1 and 2.For example, the substrate may include an angled reflective surface toimprove out-coupling, such as a mesa structure as described in U.S. Pat.No. 6,091,195 to Forrest et al., and/or a pit structure as described inU.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated byreference in their entireties.

Unless otherwise specified, any of the layers of the various embodimentsmay be deposited by any suitable method. For the organic layers,preferred methods include thermal evaporation, ink-jet, such asdescribed in U.S. Pat. Nos. 6,013,982 and 6,087,196, which areincorporated by reference in their entireties, organic vapor phasedeposition (OVPD), such as described in U.S. Pat. No. 6,337,102 toForrest et al., which is incorporated by reference in its entirety, anddeposition by organic vapor jet printing (OVJP), such as described inU.S. patent application Ser. No. 10/233,470, which is incorporated byreference in its entirety. Other suitable deposition methods includespin coating and other solution based processes. Solution basedprocesses are preferably carried out in nitrogen or an inert atmosphere.For the other layers, preferred methods include thermal evaporation.Preferred patterning methods include deposition through a mask, coldwelding such as described in U.S. Pat. Nos. 6,294,398 and 6,468,819,which are incorporated by reference in their entireties, and patterningassociated with some of the deposition methods such as ink jet and OVJD.Other methods may also be used. The materials to be deposited may bemodified to make them compatible with a particular deposition method.For example, substituents such as alkyl and aryl groups, branched orunbranched, and preferably containing at least 3 carbons, may be used insmall molecules to enhance their ability to undergo solution processing.Substituents having 20 carbons or more may be used, and 3-20 carbons isa preferred range. Materials with asymmetric structures may have bettersolution processibility than those having symmetric structures, becauseasymmetric materials may have a lower tendency to recrystallize.Dendrimer substituents may be used to enhance the ability of smallmolecules to undergo solution processing.

Devices fabricated in accordance with embodiments of the invention maybe incorporated into a wide variety of consumer products, including flatpanel displays, computer monitors, televisions, billboards, lights forinterior or exterior illumination and/or signaling, heads up displays,fully transparent displays, flexible displays, laser printers,telephones, cell phones, personal digital assistants (PDAs), laptopcomputers, digital cameras, camcorders, viewfinders, micro-displays,vehicles, a large area wall, theater or stadium screen, or a sign.Various control mechanisms may be used to control devices fabricated inaccordance with the present invention, including passive matrix andactive matrix. Many of the devices are intended for use in a temperaturerange comfortable to humans, such as 18 degrees C. to 30 degrees C., andmore preferably at room temperature (20-25 degrees C.).

The materials and structures described herein may have applications indevices other than OLEDs. For example, other optoelectronic devices suchas organic solar cells and organic photodetectors may employ thematerials and structures. More generally, organic devices, such asorganic transistors, may employ the materials and structures.

The terms halo, halogen, alkyl, cycloalkyl, alkenyl, alkynyl, arylkyl,heterocyclic group, aryl, aromatic group, and heteroaryl are known tothe art, and are defined in U.S. Pat. No. 7,279,704 at cols. 31-32,which are incorporated herein by reference.

A compound comprising a heteroleptic iridium complex having the formula:

Formula I, is provided. R₁, R₃, R₄, R₅ and R₆ represent mono-, di-, tri-or tetra-substitution. R₁, R₂, R₃, R₄, R₅ and R₆ are each independentlyselected from the group consisting of hydrogen, deuterium, halide,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof. Additionally,R₁, R₃, R₄, R₅ and R₆ are optionally fused and may be furthersubstituted, and n is 1 or 2.

In one embodiment, n is 2. In another embodiment, n is 1.

In one embodiment, R₂ is aryl or substituted aryl. In anotherembodiment, R₂ is a 2,6-disubstituted aryl. In one embodiment, R₂ isalkyl. In another embodiment, R₂ is

Compounds of Formula I were found to have broad yellow emissionprofiles, which is useful for both display and lighting applicationswhere white light is necessary. Compounds of Formula I are also readilysublimed, enabling efficient purification and subsequent incorporationinto OLEDs. In some instances, having alkyl substitution at R₆ candecrease the sublimation temperatures of compounds of Formula I withoutaffecting the stability of the complex. Appropriate substitution at theR₂ position can increase the stability of compounds of Formula I.Without being bound by theory, it is believed that the use of2,6-disubstituted aryl moieties can be advantageous due to increasedsteric bulk around the iridium center, which decreases the solid statepacking of the compound, resulting in higher quantum efficiency andimproved sublimation properties.

In one embodiment, R₃, R₄, R₅ and R₆ are each independently selectedfrom the group consisting of hydrogen and alkyl, and wherein at leastone of R₃, R₄, R₅ and R₆ is alkyl. In one embodiment, R₅ is aryl. Inanother embodiment, R₆ is aryl.

In one embodiment, R₁, R₃, and R₅ are hydrogen.

Specific non-limiting examples of a compound of Formula I are provided.In one embodiment, the compound is selected from the group consistingof:

A first device is also provided. The first device comprises a firstorganic light emitting device, further comprising an anode, a cathode,and an organic layer, disposed between the anode and the cathode,comprising a compound having the formula:

R₁, R₃, R₄, R₅ and R₆ represent mono-, di-, tri- or tetra-substitution.R₁, R₂, R₃, R₄, R₅ and R₆ are each independently selected from the groupconsisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof. Additionally, R₁, R₃, R₄,R₅ and R₆ are optionally fused and may be further substituted, and n is1 or 2.

In one embodiment, the organic layer is an emissive layer and thecompound is an emissive dopant. In one embodiment, the organic layer isan emissive layer and the compound is a non-emissive dopant. In anotherembodiment, the organic layer further comprises a host.

In one embodiment, the host comprises a triphenylene containingbenzo-fused thiophene or benzo-fused furan, wherein any substituent inthe compound is an unfused substituent independently selected from thegroup consisting of C_(n)H_(2n+1), OC_(n)H_(2n+1), OAr₁,N(C_(n)H_(2n+1))₂, N(Ar₁)(Ar₂), CH═CH—C_(n)H_(2n+1), C≡CHC_(n)H_(2n+1),Ar₁, Ar₁—Ar₂, C_(n)H_(2n)—Ar₁, or no substitution. Ar₁ and Ar₂ areindependently selected from the group consisting of benzene, biphenyl,naphthalene, triphenylene, carbazole, and heteroaromatic analogsthereof, and n is from 1 to 10.

In one embodiment, the host has the formula:

In one embodiment, the host is a metal complex.

As discussed above, OLEDs that incorporate compounds of Formula I havebroad yellow emission profiles, as well as high quantum efficiencies andlong commercial lifetimes. A device capable of broad yellow emission isparticularly desirable in white illumination sources.

The quality of white illumination sources can be fully described by asimple set of parameters. The color of the light source is given by itsCIE chromaticity coordinates x and y (1931 2-degree standard observerCIE chromaticity). The CIE coordinates are typically represented on atwo dimensional plot. Monochromatic colors fall on the perimeter of thehorseshoe shaped curve starting with blue in the lower left, runningthrough the colors of the spectrum in a clockwise direction to red inthe lower right. The CIE coordinates of a light source of given energyand spectral shape will fall within the area of the curve. Summing lightat all wavelengths uniformly gives the white or neutral point, found atthe center of the diagram (CIE x,y-coordinates, 0.33, 0.33). Mixinglight from two or more sources gives light whose color is represented bythe intensity weighted average of the CIE coordinates of the independentsources. Thus, mixing light from two or more sources can be used togenerate white light.

When considering the use of these white light sources for illumination,the CIE color rendering index (CRI) may be considered in addition to theCIE coordinates of the source. The CRI gives an indication of how wellthe light source will render colors of objects it illuminates. A perfectmatch of a given source to the standard illuminant gives a CRI of 100.Though a CRI value of at least 70 may be acceptable for certainapplications, a preferred white light source may have a CRI of about 80or higher.

The compounds of Formula I have yellow emission profiles withsignificant red and green components. The addition of a blue emitter,i.e. an emitter with a peak wavelength of between 400 to 500 nanometers,together with appropriate filters on OLEDs incorporating the compound ofFormula I allows for the reproduction of the RGB spectrum. In someembodiments, OLEDs that incorporate compounds of Formula I are used forcolor displays (or lighting applications) using only two types ofemissive compounds: a yellow emitter of Formula I and a blue emitter. Acolor display using only two emissive compounds: a broad yellow emitterof Formula I and a blue emitter, may employ a color filter toselectively pass the red, green, and blue color components of a display.The red and green components can both come from a broad yellow emitterof Formula I.

In one embodiment, the first device is a consumer product. In anotherembodiment, the first device is an organic light-emitting device. In oneembodiment, the first device further comprises a second emissive dopanthaving a peak wavelength of between 400 to 500 nanometers. In oneembodiment, the second emissive dopant is a fluorescent emitter. Inanother embodiment, the second emissive dopant is a phosphorescentemitter.

In one embodiment, the first device comprises a lighting panel. In oneembodiment, the first device further comprises a first organiclight-emitting device comprising a compound of Formula I and a secondlight-emitting device separate from the first organic light-emittingdevice comprising an emissive dopant having a peak wavelength of between400 to 500 nanometers. The first and second light-emitting devices canbe placed in any suitable spatial arrangement, depending on the needs ofthe desired display or lighting application.

In another embodiment, the first device comprises an organic-lightemitting device having a first emissive layer comprising a compound ofFormula I and a second emissive layer comprising an emissive dopanthaving a peak wavelength of between 400 to 500 nanometers. In thisembodiment, the compound of Formula I and a blue emitter are locatedwithin the same OLED stack. The first emissive layer and the secondemissive layer may have one or more other layers in between them.

Device Examples

All example devices were fabricated by high vacuum (<10⁻⁷ Torr) thermalevaporation. The anode electrode is 1200 Å of indium tin oxide (ITO).The cathode consisted of 10 Å of LiF followed by 1,000 Å of Al. Alldevices are encapsulated with a glass lid sealed with an epoxy resin ina nitrogen glove box (<1 ppm of H₂O and O₂) immediately afterfabrication, and a moisture getter was incorporated inside the package.

The organic stack of the device examples consisted of sequentially, fromthe ITO surface, 100 Å of Compound A as the hole injection layer (HIL),300 Å of 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (alpha-NPD) asthe hole transporting layer (HTL), 300 Å of 10-15 wt % of compound ofFormula I doped in with Compound B as host as the emissive layer (EML),50 Å or 100 Å of Compound B as blocking layer (BL), 400 Å of Alq(tris-8-hydroxyquinoline aluminum) as the electron transport layer(ETL).

The device results and data are summarized in Tables 1 and 2 from thosedevices. As used herein, NPD, Alq, Compound A, Compound B, and CompoundX have the following structures:

TABLE 1 VTE Phosphorescent OLEDs Example HIL HTL EML (300 Å, doping %)ETL 2 ETL 1 Example 1 Compound NPD Compound Compound Compound Alq Comp.58 A 100 Å 300 Å B 58 10% B 50 Å 400 Å Example 2 Compound NPD CompoundCompound Compound Alq Comp. 30 A 100 Å 300 Å B 30 10% B 50 Å 400 ÅCompar- Compound NPD Compound Compound Compound Alq ative A 100 Å 300 ÅB X 10% B 100 Å 400 Å Example Comp. X

TABLE 2 VTE Device Data FWHM Voltage LE EQE PE LT80% Example x y λ_(max)(nm) (V) (Cd/A) (%) (lm/W) (h) Example 1 0.504 0.491 572 78 6.1 59.120.3 30.3 505 Comp. 58 Example 2 0.450 0.540 558 74 5.9 58.7 17.4 31.4280 Comp. 30 Compar- 0.325 0.620 519 72 5.7 50.5 14.0 27.6 270 ativeExample Comp. X

The device data show that Compounds of Formula I are effective yellowemitters with broad line shape (desirable for use in white lightdevices), with high efficiency and commercially useful lifetimes.Comparative Example Compound X is a green emitter, emitting at a peakwavelength of 519 nm, with a FWHM (full width at half max) of 72 nm. Byadding an additional phenyl ring to the pyridine ring, Compound 58emitted at 572 nm and Compound 30 emitted at 558 nm, showing a red-shiftin their emission spectra while broadening the emission to a FWHM of 78nm and 74 nm respectively, which make them useful broad emitters forwhite light applications. In addition, compounds of Formula I havehigher efficiencies [Compound 58 (59.1 cd/A, 20.3%, 30.3 μm/W) andCompound 30 (58.7 μm/W, 17.4%, 31.4 lm/W)] versus the comparativeexample (50.5 cd/A, 14.0%, 27.6 μm/W) while maintaining comparablevoltages. Finally, Compound 30 has a slightly higher device lifetime(280 h) than Comparative Compound X (270 h), while Compound 30 has adevice lifetime almost twice as long (505 h).

Combination with Other Materials

The materials described herein as useful for a particular layer in anorganic light emitting device may be used in combination with a widevariety of other materials present in the device. For example, emissivedopants disclosed herein may be used in conjunction with a wide varietyof hosts, transport layers, blocking layers, injection layers,electrodes and other layers that may be present. The materials describedor referred to below are non-limiting examples of materials that may beuseful in combination with the compounds disclosed herein, and one ofskill in the art can readily consult the literature to identify othermaterials that may be useful in combination.

HIL/HTL:

A hole injecting/transporting material to be used in the presentinvention is not particularly limited, and any compound may be used aslong as the compound is typically used as a hole injecting/transportingmaterial. Examples of the material include, but not limit to: aphthalocyanine or porphryin derivative; an aromatic amine derivative; anindolocarbazole derivative; a polymer containing fluorohydrocarbon; apolymer with conductivity dopants; a conducting polymer, such asPEDOT/PSS; a self-assembly monomer derived from compounds such asphosphonic acid and sliane derivatives; a metal oxide derivative, suchas MoO_(x); a p-type semiconducting organic compound, such as1,4,5,8,9,12-Hexaazatriphenylenehexacarbonitrile; a metal complex, and across-linkable compounds.

Examples of aromatic amine derivatives used in HIL or HTL include, butnot limit to the following general structures:

Each of Ar¹ to Ar⁹ is selected from the group consisting aromatichydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl,triphenylene, naphthalene, anthracene, phenalene, phenanthrene,fluorene, pyrene, chrysene, perylene, azulene; group consisting aromaticheterocyclic compounds such as dibenzothiophene, dibenzofuran,dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene,benzoselenophene, carbazole, indolocarbazole, pyridylindole,pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole,oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine,pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine,indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole,benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline,quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine,phenazine, phenothiazine, phenoxazine, benzofuropyridine,furodipyridine, benzothienopyridine, thienodipyridine,benzoselenophenopyridine, and selenophenodipyridine; and groupconsisting 2 to 10 cyclic structural units which are groups of the sametype or different types selected from the aromatic hydrocarbon cyclicgroup and the aromatic heterocyclic group and are bonded to each otherdirectly or via at least one of oxygen atom, nitrogen atom, sulfur atom,silicon atom, phosphorus atom, boron atom, chain structural unit and thealiphatic cyclic group. Wherein each Ar is further substituted by asubstituent selected from the group consisting of hydrogen, deuterium,halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinationsthereof.

In one aspect, Ar¹ to Ar^(g) is independently selected from the groupconsisting of:

k is an integer from 1 to 20; X¹ to X⁸ is C (including CH) or N; Ar¹ hasthe same group defined above.

Examples of metal complexes used in HIL or HTL include, but not limit tothe following general formula:

M is a metal, having an atomic weight greater than 40; (Y¹—Y²) is abidentate ligand, Y¹ and Y² are independently selected from C, N, O, P,and S; L is an ancillary ligand; m is an integer value from 1 to themaximum number of ligands that may be attached to the metal; and m+n isthe maximum number of ligands that may be attached to the metal.

In one aspect, (Y¹—Y²) is a 2-phenylpyridine derivative.

In another aspect, (Y¹—Y²) is a carbene ligand.

In another aspect, M is selected from Ir, Pt, Os, and Zn.

In a further aspect, the metal complex has a smallest oxidationpotential in solution vs. Fc⁺/Fc couple less than about 0.6 V.

Host:

The light emitting layer of the organic EL device of the presentinvention preferably contains at least a metal complex as light emittingmaterial, and may contain a host material using the metal complex as adopant material. Examples of the host material are not particularlylimited, and any metal complexes or organic compounds may be used aslong as the triplet energy of the host is larger than that of thedopant.

Examples of metal complexes used as host are preferred to have thefollowing general formula:

M is a metal; (Y³—Y⁴) is a bidentate ligand, Y³ and Y⁴ are independentlyselected from C, N, O, P, and S; L is an ancillary ligand; m is aninteger value from 1 to the maximum number of ligands that may beattached to the metal; and m+n is the maximum number of ligands that maybe attached to the metal.

In one aspect, the metal complexes are:

(O—N) is a bidentate ligand, having metal coordinated to atoms O and N.

In another aspect, M is selected from Ir and Pt.

In a further aspect, (Y³—Y⁴) is a carbene ligand.

Examples of organic compounds used as host are selected from the groupconsisting aromatic hydrocarbon cyclic compounds such as benzene,biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene,phenanthrene, fluorene, pyrene, chrysene, perylene, azulene; groupconsisting aromatic heterocyclic compounds such as dibenzothiophene,dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran,benzothiophene, benzoselenophene, carbazole, indolocarbazole,pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole,oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole,pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine,oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine,benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline,cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine,pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine,benzofuropyridine, furodipyridine, benzothienopyridine,thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine;and group consisting 2 to 10 cyclic structural units which are groups ofthe same type or different types selected from the aromatic hydrocarboncyclic group and the aromatic heterocyclic group and are bonded to eachother directly or via at least one of oxygen atom, nitrogen atome,sulfur atom, silicon atom, phosphorus atom, boron atom, chain structuralunit and the aliphatic cyclic group. Wherein each group is furthersubstituted by a substituent selected from the group consisting ofhydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof.

In one aspect, host compound contains at least one of the followinggroups in the molecule:

R¹ to R⁷ is independently selected from the group consisting ofhydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl,heteroalkyl, aryl and heteroaryl, when it is aryl or heteroaryl, it hasthe similar definition as Ar's mentioned above.

k is an integer from 0 to 20.

X¹ to X⁸ is selected from C (including CH) or N.

HBL:

A hole blocking layer (HBL) may be used to reduce the number of holesand/or excitons that leave the emissive layer. The presence of such ablocking layer in a device may result in substantially higherefficiencies as compared to a similar device lacking a blocking layer.Also, a blocking layer may be used to confine emission to a desiredregion of an OLED.

In one aspect, compound used in HBL contains the same molecule used ashost described above.

In another aspect, compound used in HBL contains at least one of thefollowing groups in the molecule:

k is an integer from 0 to 20; L is an ancillary ligand, m is an integerfrom 1 to 3.

ETL:

Electron transport layer (ETL) may include a material capable oftransporting electrons. Electron transport layer may be intrinsic(undoped), or doped. Doping may be used to enhance conductivity.Examples of the ETL material are not particularly limited, and any metalcomplexes or organic compounds may be used as long as they are typicallyused to transport electrons.

In one aspect, compound used in ETL contains at least one of thefollowing groups in the molecule:

R¹ is selected from the group consisting of hydrogen, alkyl, alkoxy,amino, alkenyl, alkynyl, arylalkyl, heteroalkyl, aryl and heteroaryl,when it is aryl or heteroaryl, it has the similar definition as Ar'smentioned above.

Ar¹ to Ar³ has the similar definition as Ar's mentioned above.

k is an integer from 0 to 20.

X¹ to X⁸ is selected from C (including CH) or N.

In another aspect, the metal complexes used in ETL contains, but notlimit to the following general formula:

(O—N) or (N—N) is a bidentate ligand, having metal coordinated to atomsO, N or N, N;

L is an ancillary ligand; m is an integer value from 1 to the maximumnumber of ligands that may be attached to the metal.

In any above-mentioned compounds used in each layer of the OLED device,the hydrogen atoms can be partially or fully deuterated.

In addition to and/or in combination with the materials disclosedherein, many hole injection materials, hole transporting materials, hostmaterials, dopant materials, exiton/hole blocking layer materials,electron transporting and electron injecting materials may be used in anOLED. Non-limiting examples of the materials that may be used in an OLEDin combination with materials disclosed herein are listed in Table 3below. Table 3 lists non-limiting classes of materials, non-limitingexamples of compounds for each class, and references that disclose thematerials.

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EXPERIMENTAL

Chemical abbreviations used throughout this document are as follows: Cyis cyclohexyl, dba is dibenzylideneacetone, EtOAc is ethyl acetate.

Example 1 Synthesis of Condensation Product of Benzaldehyde andN-(2,6-diisopropylphenyl)benzene-1,2-diamine

1-Bromo-2-nitrobenzene (15 g, 75 mmol), 2,6-diisopropylaniline (14.0 mL,75 mmol) and cesium carbonate (41.5 g, 127 mmol) were mixed in 500 mL oftoluene and the solution was bubbled with nitrogen for 20 min. Pd₂(dba)₃(1.36 g, 1.49 mmol) anddicyclohexyl(2′,6′-dimethoxy-[1,1′-biphenyl]-2-yl)phosphine (2.44 g,5.94 mmol) were added and reaction mixture was heated to reflux for 18h. After cooling, the organic layer separated and the aqueous layer wasextracted with 3×50 mL dichloromethane and dried over sodium sulfate.After removing the solvent under reduced pressure, the crude product waschromatographed on silica gel with 10:90 (v/v) ethyl acetate:hexane and20 g (72%) of the product was obtained. The product was confirmed byGC/MS, NMR and HPLC (99.96% pure)

2,6-Diisopropyl-N-(2-nitrophenyl) aniline (12 g, 40.2 mmol) wasdissolved in 200 mL ethanol and palladium on carbon (0.642 g) was added.The reaction mixture was placed on the Parr hydrogenator for 1 h. Thereaction mixture was filtered through a Celite® plug, washed withdichloromethane and evaporated. The crude product was chromatographed onsilica gel with 10:90 (v/v) ethyl acetate:hexane and 10 g (93%) of theproduct was obtained. The product was confirmed by GC/MS and NMR.

N-(2,6-Diisopropylphenyl)benzene-1,2-diamine (16.5 g, 61.5 mmol),benzaldehyde (9.8 mL, 92 mmol) and 1-hexadecylpyridinium bromide (1.2 g,3.1 mmol) were dissolved in 50 mL THF and 500 mL water and stirred atroom temperature overnight. By GC/MS the reaction mixture typicallyshowed a mixture of the phenylbenzimidazole product and thephenyl-2,3-dihydro-1H-benzo[d]imidazole product (ca. 50:50). Brine (200mL) was added and the reaction mixture extracted with EtOAc (3×300 mL),dried over sodium sulfate and evaporated. The total crude yield was 20 g(˜91%) and was carried onto the next step.

Example 2 Reaction of Condensation Product of Benzaldehyde andN-(2,6-diisopropylphenyl)benzene-1,2-diamine with Manganese (IV) Oxide

The mixture of the phenylbenzimidazole product and thephenyl-2,3-dihydro-1H-benzo[d]imidazole product (18 g, 50.5 mmol)obtained as in Example 1 was combined and manganese(IV) oxide (22 g, 252mmol) in 300 mL of toluene. With vigorous stirring, the reaction washeated to reflux for 10 h, cooled, filtered through a plug of silica geleluted with dichloromethane and evaporated. The crude product waschromatographed on silica gel with 0-3% ethyl acetate in dichloromethaneand then recrystallized from hexane to give 14.7 g (82%) of the product.The product was confirmed by HPLC (>98%) and NMR. Yields ranged from48-75%.

Example 3

To a 1 L round bottom flask was added 4-chloro-2-phenylpyridine (3.31 g,17.44 mmol), naphthalen-2-ylboronic acid (3.0 g, 17.44 mmol),dicyclohexyl(2′,6′-dimethoxy-[1,1′-biphenyl]-2-yl)phosphine (0.286 g,0.698 mmol) and potassium phosphate tribasic monohydrate (12.1 g, 52.3mmol) with toluene 250 mL and water 25 mL. The reaction mixture wasdegassed with N₂ for 20 minutes. Pd₂(dba)₃ (0.319 g, 0.349 mmol) wasadded and the reaction mixture was refluxed for 18 h. After cooling, theaqueous layer was removed and toluene was evaporated under reducedpressure. The residue was dissolved in dichloromethane and passedthrough one inch silica gel plug on a fit, eluting with dichloromethane.The crude product was chromatographed on silica gel with 20-25% ethylacetate in hexane to give 3 g (61%) of the product. The product wasconfirmed by HPLC (100% purity) and GC/MS.

Example 4

To a round-bottom flask was added1-(2,6-diisopropylcyclohexa-2,4-dien-1-yl)-2-phenyl-1H-benzo[d]imidazole(6.0 g, 16.83 mmol) and iridium (III) chloride hydrate (1.98 g, 5.61mmol) with 2-ethoxyethanol (100 mL) and water (33 mL) under N₂atmosphere. The resulting reaction mixture was refluxed at 130° C. for18 h. The yellow precipitate was filtered, washed with methanol (3-4times) and hexane (3-4 times) to yield 5.2 g (98.8%) of a yellow solidafter drying. The product was used without further purification.

Example 5

In a round-bottom flask, the iridium dimer complex obtained as inExample 4 (5.2 g, 2.78 mmol) was dissolved in 200 mL dichloromethane. Ina separate flask, silver(I) triflate (1.5 g, 5.84 mmol) was dissolved in250 mL of MeOH. This was added slowly to the dimer solution withcontinuous stirring at room temperature. The reaction mixture wasstirred overnight in the dark, then filtered through a tightly packedCelite® bed to remove silver chloride precipitate. The solvent wasremoved under reduced pressure to give 6.0 g (100%) of a brownish greensolid and used without further purification.

Example 6 Synthesis of Compound 58

To a flask was added the iridium triflate complex obtained as in Example5 (3.0 g, 2.7 mmol) and 4-(naphthalen-2-yl)-2-phenylpyridine (3.0 g,10.7 mmol) obtained as in Example 3, 25 mL EtOH and 25 mL MeOH. Thereaction mixture was refluxed for 18 h, with a yellow-orange precipitateforming. The reaction mixture was cooled to room temperature, dilutedwith ethanol, Celite® was added and the mixture stirred for 10 min. Themixture was filtered on a small silica gel plug on a frit and washedwith ethanol (3-4 times) and with hexane (3-4 times). The filtrate wasdiscarded. The celite/silica plug was then washed with dichloromethaneto dissolve the product. Half the volume of dichloromethane was removedunder reduced pressure and isopropanol was added to precipitate theproduct, which was filtered and washed with methanol and hexane. Thecrude product was chromatographed on silica gel with 1/1 (v/v)dichloromethane/hexane and then sublimed to yield 1.4 g (44%) of productas a yellow solid. The product, Compound 58, was confirmed by HPLC(99.8% pure) and LC/MS.

Example 7 Synthesis of Compound 30

To a flask was added the iridium triflate complex (3.5 g, 3.2 mmol) and2,4-diphenylpyridine (3.5 g, 15.13 mmol), 25 mL EtOH and 25 mL MeOH. Thereaction mixture was refluxed for 18 h, with a yellow-orange precipitateforming. The reaction mixture was cooled to room temperature, dilutedwith ethanol, Celite® was added and the mixture stirred for 10 min. Themixture was filtered on a small silica gel plug on a frit and washedwith ethanol (3-4 times) and with hexane (3-4 times). The filtrate wasdiscarded. The celite/silica plug was then washed with dichloromethaneto dissolve the product. Half the volume of dichloromethane was removedunder reduced pressure and isopropanol was added to precipitate theproduct, which was filtered and washed with methanol and hexane. Thecrude product was chromatographed on silica gel with 1/1 (v/v)dichloromethane/hexane and then sublimed to yield 1.9 g (54%) of productas a yellow solid. The product, Compound 30, was confirmed by HPLC(99.9% pure) and LC/MS.

It is understood that the various embodiments described herein are byway of example only, and are not intended to limit the scope of theinvention. For example, many of the materials and structures describedherein may be substituted with other materials and structures withoutdeviating from the spirit of the invention. The present invention asclaimed may therefore includes variations from the particular examplesand preferred embodiments described herein, as will be apparent to oneof skill in the art. It is understood that various theories as to whythe invention works are not intended to be limiting.

1. A compound comprising a heteroleptic iridium complex having theformula:

wherein R₁, R₃, R₄, R₅ and R₆ represent mono-, di-, tri- ortetra-substitution; wherein R₁, R₂, R₃, R₄, R₅ and R₆ are eachindependently selected from the group consisting of hydrogen, deuterium,halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfanyl, sulfonyl, phosphino, and combinationsthereof; wherein R₁, R₃, R₄, R₅ and R₆ are optionally fused and may befurther substituted; and wherein n=1 or
 2. 2. The compound of claim 1,wherein n=2.
 3. The compound of claim 1, wherein n=1.
 4. The compound ofclaim 1, wherein R₂ is aryl or substituted aryl.
 5. The compound ofclaim 4, wherein R₂ is a 2,6-disubstituted aryl.
 6. The compound ofclaim 5, wherein R₂ is


7. The compound of claim 1, wherein R₂ is alkyl.
 8. The compound ofclaim 1, wherein R₃, R₄, R₅ and R₆ are each independently selected fromthe group consisting of hydrogen and alkyl, and wherein at least one ofR₃, R₄, R₅ and R₆ is alkyl.
 9. The compound of claim 1, wherein R₅ isaryl.
 10. The compound of claim 1, wherein R₆ is aryl.
 11. The compoundof claim 1, wherein R₁, R₃, and R₅ are hydrogen.
 12. The compound ofclaim 1, wherein the compound is selected from the group consisting of:


13. A first device comprising a first organic light emitting device,further comprising: an anode; a cathode; and an organic layer, disposedbetween the anode and the cathode, comprising a compound having theformula:

wherein R₁, R₃, R₄, R₅ and R₆ represent mono-, di-, tri- ortetra-substitution; wherein R₁, R₂, R₃, R₄, R₅ and R₆ are eachindependently selected from the group consisting of hydrogen, deuterium,halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinationsthereof; wherein R₁, R₃, R₄, R₅ and R₆ are optionally fused and may befurther substituted; and wherein n=1 or
 2. 14. The first device of claim13, wherein the organic layer is an emissive layer and the compound isan emissive dopant.
 15. The first device of claim 13, wherein theorganic layer is an emissive layer and the compound is a non-emissivedopant.
 16. The first device of claim 13, wherein the organic layerfurther comprises a host.
 17. The first device of claim 16, wherein thehost comprises a triphenylene containing benzo-fused thiophene orbenzo-fused furan; wherein any substituent in the host is an unfusedsubstituent independently selected from the group consisting ofC_(n)H_(2n+1), OC_(n)H_(2n+1), OAr₁, N(C_(n)H_(2n+1))₂, N(Ar₁)(Ar₂),CH═CH—C_(n)H_(2n+1), C≡CHC_(n)H_(2n+1), Ar₁, Ar₁—Ar₂, C_(n)H_(2n)—Ar₁,or no substitution; wherein n is from 1 to 10; and wherein Ar₁ and Ar₂are independently selected from the group consisting of benzene,biphenyl, naphthalene, triphenylene, carbazole, and heteroaromaticanalogs thereof.
 18. The first device of claim 17, wherein the host hasthe formula:


19. The first device of claim 16, wherein the host is a metal complex.20. The first device of claim 13 wherein the first device is a consumerproduct.
 21. The first device of claim 13, wherein the first device isan organic light-emitting device.
 22. The first device of claim 13,wherein the first device further comprises a second emissive dopanthaving a peak wavelength of between 400 to 500 nanometers.
 23. The firstdevice of claim 22, wherein the second emissive dopant is a fluorescentemitter.
 24. The first device of claim 22, wherein the second emissivedopant is a phosphorescent emitter.
 25. The first device of claim 13,wherein the first device comprises a lighting panel.
 26. The firstdevice of claim 13, wherein the first device further comprises a firstorganic light-emitting device comprising a compound of Formula I and asecond light emitting device separate from the first organiclight-emitting device comprising an emissive dopant having a peakwavelength of between 400 to 500 nanometers.
 27. The first device ofclaim 13, wherein the first device comprises an organic-light emittingdevice having a first emissive layer and a second emissive layer;wherein the first emissive layer comprises a compound of Formula I; andwherein the second emissive layer comprises an emissive dopant having apeak wavelength of between 400 to 500 nanometers.